1. Technical Field
The present invention relates to a position measuring system.
2. Background Information
One such position measuring system is described in International Patent Disclosure WO 02/40947 A1. It has a measurement graduation substrate, which is scanned in contactless fashion by a scanning head for position measurement. For position measurement, it is necessary that the substrate of the measurement graduation be secured in a predetermined location relative to the scanning head on the machine parts that are to be measured. This purpose is served by a mounting aid, which fixes the substrate in a predetermined mounting position on the scanning head. In order to reach this mounting position, it is proposed according to WO 02/40947 A1 that the location of the scanning head relative to the substrate of the measurement graduation be calibrated in a separate operation, before the scanning head is positionally fixed on the substrate.
Increasingly, greater measurement precision is being demanded. This measurement precision is affected by the association of the scanning head and the measurement graduation. It has been demonstrated that by the known position measuring system, it is possible only with difficulty to achieve an association, required for the sake of precise position measurement, between the scanning head and the substrate of the measurement graduation. The two-stage procedure of calibration and positional fixation makes an exact association in the requisite mounting position possible but only inconveniently.